This invention relates generally to a protective device for use with a so-called felt tip pen to prevent ink from contacting or bleeding under a ruling edge, such as the straight edge of a ruler or the like.
Felt tip pens in general are known in the art and typically comprise an elongated pen body or barrel which supports at one end an outwardly projecting nib. This nib is formed from a porous material, such as a compressed bundle of natural and/or synthetic fibers, commonly referred to as "felt", to have a generally rectangular cross section terminating at its end opposite the barrel in a rectangular-shaped writing tip to which ink is transferred from within the barrel by capillary action. This writing tip is typically cut at an oblique angle to permit full-surface engagement thereof with a selected writing surface, such as paper, poster board, or the like, while the pen is held at a comfortable and normal writing angle. As is well known, felt tip pens can be used to draw a relatively broad or comparatively narrow line depending upon the direction in which the writing tip is moved over the writing surface.
Felt tip pens of the type described are available in a variety of different colors, and as a result, these pens are used by many artists in the production of a wide variety of artistic works. However, significant problems are encountered with such pens when the nib thereof is guided over the writing surface by a ruling edge, such as the edge of a ruler, French curve, or the like, to form a line having a particular shape. Specifically, the ink-soaked nib directly contacts the ruling edge to leave an ink residue thereon which, if the ruling edge is not wiped clean after each use, can be picked up and transferred to the writing surface by a subsequently used pen. This is particularly undesirable when the subsequently used pen carries ink of a different color, since the transferred residue tends to discolor the line being drawn.
In addition, when the felt nib is guided over a writing surface by a ruling edge, the ink carried by the nib sometimes bleeds beneath the ruling edge. This results in a drawn line with an unintended fuzzy or smudged boundary which is highly unattractive in appearance.
There exists, therefore, a significant need for a device which can be used with a felt tip pen to prevent the felt nib of the pen from contacting a ruling edge during use. The present invention fulfills this need.